Hi I have a new plant installed in August 2025 this year. PV Production is total 13,6 Kwp together with a Battery of 14,4 Kwh . The Inverter is a H3 Smart and the Battery is a Hybrid ECS 2900-H5. After noting the data from my Fox App together with the data of my electric meter I recognized that there are major differences in the amount. The data of electric meter are much higher than the data of my App.
My major question is : Is the amount of PV Production from my Inverter correct ?
Which data gives me the exact amount of used power of my House ?
If the App data of ToGrid and From Grid is wrong what affect does this have to all other data of the App ?
Fox could not help me so far, neither did the supplier of my plant !
If the amount of From Grid is wrong is the Load Consumption also wrong ?
If the To Grid amount is wrong is the Self-Consumption also wrong ?
I am very confused and nobody is able to help me answer my questions !
Hope someone can do ?
Last edited by Turbowilly on Sun Nov 23, 2025 11:09 am, edited 1 time in total.
How far out are your values, can you give some examples of grid / load / PV ?
In general the inverter grid data is not as accurate as the electricity supplier, the meter they use is very accurate and also takes into account power factor.
The inverter meter should be within a few % accuracy, it gets worse at low loads (=~ 5%)
The PV Production reported by the app is correct, this is the actual amount of power in watts your PV array has generated.... but there are losses to take into account. A colleague has drawn this schematic which explains the losses you will experience in the gathering and conversion of power from DC to AC https://github.com/TonyM1958/HA-FoxESS- ... it-work%3F
What these losses mean is that you will appear to lose a few kWh's of power each day which may explain some of the discrepancies you are seeing.
In general the inverter grid data is not as accurate as the electricity supplier, the meter they use is very accurate and also takes into account power factor.
The inverter meter should be within a few % accuracy, it gets worse at low loads (=~ 5%)
The PV Production reported by the app is correct, this is the actual amount of power in watts your PV array has generated.... but there are losses to take into account. A colleague has drawn this schematic which explains the losses you will experience in the gathering and conversion of power from DC to AC https://github.com/TonyM1958/HA-FoxESS- ... it-work%3F
What these losses mean is that you will appear to lose a few kWh's of power each day which may explain some of the discrepancies you are seeing.
For example the value of the App for In Grid shows 1290 Kwh although the electric meter shows 1568 Kwh.
The value of the App for To Grid shows 462,6 Kwh although the electric meter shows 666 kwh.
The value of the App for To Grid shows 462,6 Kwh although the electric meter shows 666 kwh.
I need to mention that I have contacted Fox to try to get both data same the data of the App with the data of the electric meter. They said this is not possible !
Yes i’d agree that you can’t get the data precisely the same but it should be within a few %
Those are interesting numbers you have provided, does your electricity supplier use net metering ?… the 3 phase inverter is balanced so for example (assuming you have an H3-12 ~ 4kw per phase) when producing 6kW of PV it will output that as 2kW per phase, however if you have a 5kW load on one phase then as the inverter can only supply 4kW for each phase and making up the surplus from the battery it will draw 1kW on that phase from grid.
If your electricity supplier is using net metering they should see 2kW export on 2 phases, and 1 kW input on the other which is a net metering of (2+2-1) =3kW export with no import, but if they are not net metering then they will report 1kW import and 4kW export. If that is the case it would inflate your electric meter grid import and your export figures much as you have said - is that a possibility ?
Those are interesting numbers you have provided, does your electricity supplier use net metering ?… the 3 phase inverter is balanced so for example (assuming you have an H3-12 ~ 4kw per phase) when producing 6kW of PV it will output that as 2kW per phase, however if you have a 5kW load on one phase then as the inverter can only supply 4kW for each phase and making up the surplus from the battery it will draw 1kW on that phase from grid.
If your electricity supplier is using net metering they should see 2kW export on 2 phases, and 1 kW input on the other which is a net metering of (2+2-1) =3kW export with no import, but if they are not net metering then they will report 1kW import and 4kW export. If that is the case it would inflate your electric meter grid import and your export figures much as you have said - is that a possibility ?
Hi Dave
as what I have understood the are not using net metering ! I had a mechanic checking my plant 2 weeks ago and he said that from the electrical installation with my inverter everything is ok ! Within the last month I have opened several Tickets with Fox to get my problem solved but with no really satisfying result. Fox made some changes on my plant as following:
Meter compensation to -200
Standby State to disable
Standby Load Power Threshold to 200
as what I have understood the are not using net metering ! I had a mechanic checking my plant 2 weeks ago and he said that from the electrical installation with my inverter everything is ok ! Within the last month I have opened several Tickets with Fox to get my problem solved but with no really satisfying result. Fox made some changes on my plant as following:
Meter compensation to -200
Standby State to disable
Standby Load Power Threshold to 200
Ok, that stacks up then with your extra few hundred kWh’s, if you deduct the difference between the 2 import measurements, and compare that with the difference between your 2 export figures you are very close (the difference being system losses)
There should be an installer configurable option on the inverter to run in unbalanced mode, that might be more suitable for you depending on whether you get paid more for export than import but i’ll leave you to discuss with your installer / Fox..
There should be an installer configurable option on the inverter to run in unbalanced mode, that might be more suitable for you depending on whether you get paid more for export than import but i’ll leave you to discuss with your installer / Fox..
Dave
If you say the data of PV Production is correct what about the other data. Will the huge difference have any influence in the Load Consumption together with Self-Sufficiency and To Load & Battery ( Self-Consumption ) ??
If you say the data of PV Production is correct what about the other data. Will the huge difference have any influence in the Load Consumption together with Self-Sufficiency and To Load & Battery ( Self-Consumption ) ??
Dave
Can Fox change my Inverter to inverter to run in unbalanced mode ? I can´t make any changes in my Inverter. Will this help to get correct data ?
Can Fox change my Inverter to inverter to run in unbalanced mode ? I can´t make any changes in my Inverter. Will this help to get correct data ?
Yes Fox can change it remotely, net metering really needs the system to be balanced, but if you are not then the 2 meters are performing different calculations.
It’s worth discussing it with them in detail as I believe a balanced inverter is more efficient than an un-balanced one, and in an ideal world if the cost of electricity import was the same as export it wouldn’t make any difference to your bill, it would just look as it does that you have output more and used more.
I think the accuracy will be much better but it really depends on your usage per phase as if you have a high load on one phase the inverter will still only be able to output (your inverter size / 3) per phase - it’s a simple option to enable it and disable it, so easy enough for you to test out the accuracy over a couple of weeks.
It’s worth discussing it with them in detail as I believe a balanced inverter is more efficient than an un-balanced one, and in an ideal world if the cost of electricity import was the same as export it wouldn’t make any difference to your bill, it would just look as it does that you have output more and used more.
I think the accuracy will be much better but it really depends on your usage per phase as if you have a high load on one phase the inverter will still only be able to output (your inverter size / 3) per phase - it’s a simple option to enable it and disable it, so easy enough for you to test out the accuracy over a couple of weeks.
Dave thank´s for your help. I will contact Fox to get my Inverter setting changed.